Saint Gobain outlines progress on PFAS groundwater monitoring and water supply remedies

The New Hampshire Environmental Services Department held a meeting on April 15, 2025, to discuss ongoing efforts related to groundwater contamination and the management of drinking water wells affected by PFAS (per- and polyfluoroalkyl substances). The meeting highlighted significant progress in monitoring and remediation efforts, particularly concerning the activities of Saint Gobain, a company involved in the contamination issue.

During the meeting, officials reported that Saint Gobain has proposed a long-term monitoring plan for drinking water wells, which was initially outlined in June 2024 and has undergone several revisions since then. The revised work plan, approved in January 2025, aims to conduct sampling at eligible properties, with a goal of obtaining at least six PFAS sample results for each property by the end of 2026. As of early April, approximately 350 properties have been resampled, with plans to sample an additional 50 to 200 properties each month. Properties that exceed drinking water standards will continue to receive bottled water eligibility letters.

The meeting also addressed the ongoing site investigations and the need for a remedial action plan to address contamination. Officials expressed dissatisfaction with previous submissions and noted that Saint Gobain is expected to submit a new remedial action plan addendum by mid-2025, which will evaluate further remedial alternatives and address identified data gaps.

In terms of remediation progress, the meeting revealed that over 90% of point-of-entry treatment systems proposed as remedies have been implemented across various towns. However, the completion rates for water line installations vary significantly, with Londonderry lagging at approximately 3.6% completion, while other towns like Merrimack and Litchfield report higher completion rates.

The Environmental Services Department will continue to provide updates on the progress of these initiatives, with bimonthly reports expected to reflect the new sampling regime and ongoing remediation efforts. The next proposal from Saint Gobain is anticipated in May 2025, which will further outline the company's plans to address water supply issues in the affected areas.